Paracentesis is a medical procedure involving the insertion of a device into a body cavity and withdrawal of fluid therefrom. These procedures can be performed for general removal of fluid from the body cavity, or for analytical and diagnostic purposes. Thoracentesis is a paracentetic procedure involving access into the pleural cavity and removal of fluid therefrom without permitting the entry of air or backflow of fluids. The thoracentesis procedure, such as that used to treat pleural effusion, usually involves the use of a tube or catheter inserted through the chest wall and into the pleural cavity to withdraw fluid therefrom. Body fluids such as effluate and blood, as well as air, can be removed from the cavity by application of negative pressure or suction from outside the patient's body. One critical aspect to the procedure is the continual maintenance of negative pressure in the pleural cavity throughout the duration of the procedure. It is therefore, undesirable for commingling of the pleural environment and the external environment to occur, which can result in pneumothorax. Another critical aspect to the thoracentesis procedure is the avoidance of puncturing the lung tissue, which can permit the inflow of air in the lung into the pleural cavity.
A variety of device components have been developed to improve invasive devices and procedures. Puncture-resistant Veress needle assemblies are known in the art. Scarfone et al., U.S. Pat. No. 5,669,883 discloses, a Veress needle and cannula assembly where an inner and outer cannula are inserted within the catheter. Such devices, however, offer a limited extent of procedural alternatives.
There exists a need in the medical device field for an improved paracentesis device containing features which facilitate the use of the device by the practitioner and at the same time can maintain a closed environment throughout the procedure. There is also a need in the medical device field for improved paracentesis devices which afford the user alternative procedural options and flexibility of usage.